Speeding Up Social Waves. Propagation Mechanisms of Shimmering in Giant Honeybees

Abstract

Shimmering is a defence behaviour in giant honeybees (Apis dorsata), whereby bees on the nest surface flip their abdomen upwards in a Mexican wave-like process. However, information spreads faster than can be ascribed to bucket bridging, which is the transfer of information from one individual to an adjacent one. We identified a saltatoric process that speeds up shimmering by the generation of daughter waves, which subsequently merge with the parental wave, producing a new wave front. Motion patterns of individual “focus” bees (n = 10,894) and their shimmering-active neighbours (n = 459,558) were measured with high-resolution video recording and stereoscopic imaging. Three types of shimmering-active surface bees were distinguished by their communication status, termed “agents”: “Bucket-bridging” agents comprised 74.98% of all agents, affected 88.17% of their neighbours, and transferred information at a velocity of v = 0.317±0.015 m/s. “Chain-tail” agents comprised 9.20% of the agents, were activated by 6.35% of their neighbours, but did not motivate others to participate in the wave. “Generator agents” comprised 15.82% of agents, showed abdominal flipping before the arrival of the main wave front, and initiated daughter waves. They affected 6.75% of their neighbourhood and speeded up the compound shimmering process compared to bucket bridging alone by 41.5% to v = 0.514±0.019 m/s. The main direction of shimmering was reinforced by 35.82% of agents, whereas the contribution of the complementing agents was fuzzy. We discuss that the saltatoric process could enable the bees to instantly recruit larger cohorts to participate in shimmering and to respond rapidly to changes in flight direction of preying wasps. A third, non-exclusive explanation is that at a distance of up to three metres from the nest the acceleration of shimmering could notably contribute to the startle response in mammals and birds.

Variation in movement: multiple locomotor gaits in Neotropical harvestmen

“…obs.). This is similar to the defensive response of other harvestmen (Machado et al 2002) and the shimmering defensive behaviour of the giant honeybee Apis dorsata (Kastberger et al, 2014). Together, these observations support our hypothesis that running, stotting and bobbing function as predatory escape responses.…”

Giant honeybees (Apis dorsata) mob wasps away from the nest by directed visual patterns

“…The experiments were conducted with Apis dorsata nests in the village of Sauraha, at the border of the Chitwan National Park, Nepal. Preliminary experiments had been carried out in 2003 (Kastberger et al 2008 ) and in 2009 (Kastberger et al 2011b , 2012 , 2013a , b ; Weihmann et al 2012 ), but in November 2010 a single nest was selected for the much broader in-depth investigation described in this paper. This approximately 3-week-old nest was attached to a hotel balcony (Fig.…”

“…This approximately 3-week-old nest was attached to a hotel balcony (Fig. S1/Online Resource 1 ; Kastberger et al 2011b , 2012 , 2013b ; Waddoup 2014 ), it had a hemispherical form of 85 × 60 cm (width × height) with a multi-layer cover comprising approximately 15,000 individuals.…”

“…Shimmering behaviour happens exclusively in the surface layer of the bee curtain of a giant honeybee nest. In the quiescent state, the individuals hang with their heads up und their abdomens down (Kastberger et al 2011a ), but during shimmering they flip their abdomens upwards by more than 90° (Kastberger et al 2011b ) in a highly coordinated fashion which generates a Mexican wave-like process (Kastberger et al 2012 , 2013a , b ).…”

“…Giant honeybees have evolved shimmering behaviour for collective defence (Seeley et al 1982 ; Kastberger et al 2011a ; Weihmann et al 2012 ). Visual threats provoke patterns reminiscent of Mexican waves, which propagate with a characteristic velocity and in a controlled direction over the surface of a giant honeybee nest (Kastberger et al 2012 , 2013a , b ). The first 200–300 ms of a shimmering wave form a flash-like visual signal with the capacity to repel a preying wasp (Kastberger et al 2008 , 2010 ; cf.…”